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Background: The aim of this research was to investigate the retinal transcriptome changes in long-term streptozotocin (STZ)-induced rats' retinas using RNA sequencing (RNA-seq), to explore the molecular mechanisms of diabetic retinopathy (DR), and to identify novel targets for the treatment of DR by comparing the gene expression profile we obtained., Methods: In this study, 6 healthy male SD rats were randomly divided into wild-type (WT) group and streptozotocin (STZ)-induced group, 3 rats each group. After 6 months, 3 normal retina samples and 3 DM retina samples (2 retinas from the same rat were considered as 1 sample) were tested and differentially expressed genes (DEGs) were measured by RNA-seq technology. Then, we did Gene Ontology (GO) enrichment analysis and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analysis and validated the results of RNA-seq through qRT-PCR., Results: A total of 118 DEGs were identified, of which 72 were up-regulated and 46 were down-regulated. The enriched GO terms showed that 3 most significant enrichment terms were binding (molecular function), cell part (cellular component), and biological regulation (biological process). The results of the KEGG pathway analysis revealed a significant enrichment in cell adhesion molecules, PI3K-Akt signaling pathway, and allograft rejection, etc. CONCLUSION: Our research has identified specific DEGs and also speculated their potential functions, which will provide novel targets to explore the molecular mechanisms of DR., (© 2020 The Authors. Molecular Genetics & Genomic Medicine published by Wiley Periodicals, Inc.)

Endothelial glycocalyx plays a significant role in the development and progression of diabetic complications. Endomucin (EMCN) is an anti-inflammatory membrane glycoprotein that is mainly expressed in venous and capillary endothelial cells. However, the function of EMCN in diabetic retinopathy (DR) progression is still completely unknown. We first investigated the change of EMCN expression in the retina and human retinal microvascular endothelial cells. We then overexpressed EMCN in the retina with adeno-associated virus and induced DR with streptozotocin (STZ). We analyzed EMCN's effect on the integrity of endothelial glycocalyx under conditions of DR. Furthermore, we investigated EMCN's protective effect against inflammation and blood-retinal barrier (BRB) destruction. We found that EMCN is specifically expressed in retinal endothelial cells and that its levels are decreased during hyperglycemia in vitro and in vivo . Overexpression of EMCN can restore the retinal endothelial glycocalyx of STZ-induced diabetic rats. Furthermore, EMCN overexpression can decrease leukocyte-endothelial adhesion to ameliorate inflammation and stabilize the BRB to inhibit vessel leakage in rats with DR. EMCN may protect patients with diabetes from retinal vascular degeneration by restoring the endothelial glycocalyx. EMCN may thus represent a novel therapeutic strategy for DR because it targets endothelial glycocalyx degradation associated with this disease.-Niu, T., Zhao, M., Jiang, Y., Xing, X., Shi, X., Cheng, L., Jin, H., Liu, K. Endomucin restores depleted endothelial glycocalyx in the retinas of streptozotocin-induced diabetic rats.

Purpose: Angiogenesis is an essential part of the diabetes retinopathy (DR) process, and Zinc Finger RNA Binding Protein (ZFR) is important for vascularization to occur. However, the function and regulation of ZFR in DR development are not well understood. We hypothesized that high glucose condition could result in ZFR up-regulation in human retinal microvascular endothelial cells (HRMECs), thus contributing to disease progression, and O-glycosylation may be participated in this regulation., Methods: Retinas were harvested from streptozotocin (STZ)-induced rat model of diabetes. Human umbilical vein endothelial cells (HUVECs) and HRMECs cultured in high glucose concentration, and retinal tissues were detected for ZFR expression. We examined the role of ZFR on vasculogenic processes including proliferation and migration in the cell model of DR. The effect of O-glycosylation modification on ZFR was further assessed in HRMECs., Results: Expression of ZFR was up-regulated in high glucose condition both in vitro and in vivo. ZFR induced proliferation and migration of HRMECs. Inhibition of O-glycosylation modification attenuated the expression of ZFR., Conclusion: ZFR plays an important role in the pathogenesis of DR, and its mechanism may through the modification of O-glycosylation. Our research suggests that ZFR may be used as a potential prognostic marker or potential therapeutic target for DR., (Copyright © 2019 Elsevier Inc. All rights reserved.)